1. Field of the Invention
This invention relates to the dyeing of natural proteinaceous and synthetic polyamide fibers, particularly the normal and specialty nylons.
2. Description of the Prior Art
The dyeing of nylons--manufactured fibers in which the fiber-forming substance is any long chain synthetic polyamide having recurring amide groups as part of the chain--may, depending on the specific type of nylon involved--be accomplished with many different classes of dyes, e.g.: basic, acid, disperse, direct, etc. The acid and disperse dyes are in wide commercial use and the dye compositions of this invention utilize these classes of dyes. For reasons of speeding of dyeing, maximum utilization of dye and improving evenness of color throughout the dyed fiber, these dyes are generally used in conjunction with "assistants" (sometimes designated as "carriers")--materials which promote the attainment of speedy dyeing, maximum dye utilization, etc. There are a number of assistants commercially available but the experiments carried out in the work leading to this invention indicated that, generally, an assistant effective with acid dyes is not optimum for disperse dyes and vice versa. Use of only one assistant for both acid and disperse dyeing would be advantageous to a dyer in that inventories of different assistants could be reduced and there would be less possibility of erroneous selection of assistant.
It has now been found that combining certain materials which in themselves are not effective assistants both for acid and disperse dyeing of nylon and other fibers, results in combinations which are synergistically effective with both types of dyes.